Radio range



Nov. 14, 1944. n. G. c. LUCK RADIO RANGE Filed March 27, 1942 :inventor Davld Lllc Ctforneg Patented Nov. 14, 1944 RADIO RANGE David G. C. Luck, Merchantville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application March 27, 1942, Serial No. 436,430

(Cl. Z50-'11) 7 Claims.

This invention relates vto radio ranges and more especially to means for providing tone modulation of reference phase for identifying the courses and quadrants of a simultaneous four-course radio range. In an application entitled improvement in radio ranges, Serial No. 272,017, filed May 5, 1939,`by David G. C. Luck, Patent No. 2,314,795, dated March 23, 1943, there is disclosed and claimed a system of quadrant identification wherein a non-directionally radiated carrier is modulated, with a frequency re-, lated to the range tone frequency, to provide a reference phase voltage for quadrant determination. It is an object of this invention to provide means for producing and controlling a reference tone for this purpose.

The invention will be described by reference t the accompanying drawings in which Figure 1 is a schematic diagram of an apparatus used to produce from a radio frequency field with compiex modulation, a pure low frequency voltage, sub-harmonically synchronous with and accurately related in phase to one pure tone modulation component; and Figure 2 is a schematic diagram of an apparatus for producing a voltage which is a harmonic of a modulation component. Similar reference characters indicate similar elements in the drawing.

Referring to Fig. l, a loop l is placed in the vicinity of the antennas of a four-course radio range of the type described in the aforementioned application, S. N. 272,017, preferably near an on course sector in Which the A and N tones have the same polarity. The voltage picked up from the range eld is fed through a tuned radio frequency transformer 3 to a diode detector or a suitable rectifier 5, Where it is rectified to give a pulsating output similar to the envelope of the radio frequency voltage of the range field. A volume control 'I is provided for adjusting the pulsating voltage to a standard level and to compensate for `various loop installations. The range course tone frequency, which is usually 1020 cycles, is selected from the detector output by an adjustable narrow band filter 9, the output of which is half-wave rectified by a diode or suitable rectier I I feeding a slightly capacitive load I3. The voltage across the load circuit I3 is twice differentiated with respect to time by circuits I5 and I1, and the differentiated wave is amplified by an amplifier I9 to give a sequence of sharp voltage impulses repetitive at the range course tone frequency and constantly phased with respect to the eld voltage envelope component of this frequency. The filter 9, load `of the impulse frequency.

I3, differentiators I5, I'l and amplifier I9 comprise a system for deriving from a complex wave train an impulse train synchronous `with one wave component, which is described in U. S. Patent No. 2,188,611 issued January 30, 1940, to L.

rnarrow band pass filter 21, which is adjusted to pass the desired subharmonic frequency of the range course tone. This may be one-third the frequency of the range course tone, 340 cycles. One suitable filter is the feedback amplifier filter described by H. H. Scott inProceedings of the I. R. E. for February 1938, p. 226. Through an appropriate coupling device 29, such as an audio frequency transformer, the pure subharmonic tone is fed to the speech input terminals of the` carrier broadcast transmitter of the simultaneous range as is disclosed in the aforesaid application Serial No. 272,017. Therange carrier is thus modulated with a phase reference tone and transmitted uniformly in all directions. modulation `depth is set by the control 25 and the reference modulation is -brought in phase with the course modulation by the phase control 23. The necessary direct current supply volt-` ages to the unit may be provided by an ordinary socket power unit 30.

In the event that a reference tone at an odd multiple of the frequency of the range tone 'is preferred, as contemplated in the above-mentioned application Serial No. 272,017, the system illustrated in Fig. 2 may be used. As a matter of practical design, the phase control I2 is lplaced in this lower frequency circuit. The pure range course tone voltage appearing at the output of the filter 9 is fed to a limiter I0 which clips 01T the peaks, resulting in a square Wave at range course tone frequency. The desired harmonic component of this wave is selected by the filter 3l and fed to the speech input of the carrier broadcast transmitter.

Thus the invention has been described vas a unit for deriving from a radio frequency eld with complex modulation, a pure low frequency voltage subharmonically or harmonically synchronous with and accurately related-in phase to one modulation component of said field. This The is accomplished by rectifying the voltage picked up by an ,antenna placed in the field, filtering the rectied voltage to obtain a pure low frequencyvoltage Wave corresponding to the desired -modulation component, and deriving from it square Waves which are filtered to isolate the required harmonic or subharm'onic of the modulation component. i l l Y n monic voltage is used to 4modulate the carrier broadcast transmitter ofthe u sual four course simultaneous radio range, as described in applif cation S. N. 272,017, for the purpose of quadrant identification. v

Iclaim as my invention: K

1. A device for producing, from a radiation eldwith complex modulation'"aloW` frequency voltage harmonically related to one modulation component of said field, riving a radio frequency voltage from said. field, means for deriving a sinusoidal voltage'corre sponding to one of the modulation components of said radio frequency. voltage, means for. deriving from said sinusoidal voltage a square Wave having a frequency related tothe frequency of said sinusoidal Wave by an. integral number, and means for deriving. from said .Slqllare` wayea second sinusoidal Wave.'

Y 2. A device for deriving a voltage, alternating at a frequency which is. related by an. integral number to the frequency ofY one modulation component Vof a radio frequency field With *complex modulation, `comprising an antenna 91.. rectifier connected tov said. antenna, to. produce a; voltageI corresponding to the. envelope of theV amplitu'cleY radio frequencyeld in ,525@ @1117vllllfyl,v

is placed, a lterfonselectingone component of the product of.Y said rectier., a circuit for difier-V entiating. saidselected component with respectn to time and; a second circuit for difsrer113i,aljdiljg` said differentiated :component .with respect to time,v an., oscillation generator. controlled by the output ofvn said second dfferentiat ng circuit, adjustable phase shiftnglmeans arrangedtocontrol the phase. of the. Outpubrof.- said oscillation generator, an adiustable. attenuate?. f0.1. 09m.- trolling the. amplitude., oft.

related to. one.. modulation. tempomat Qf. Said.

eld, comprisinaan antennafor den ne amadulated radio freduency voltage.

responding to one modulationcqrnppnentiof said` radio.frequencrvoltaee, were Shape Ilietf This harmonic or xsubhar including'. means for de;

id. generator, Quiput. and x a lter for.; deriving. aA SnllSQidal, QQWQQ??? of. saidgeneratoroutput..

3. n deviceioraenvmg Home. radiation 161.21.

means for producing from said modulation component Voltage a train of sharply defined voltage pulses recurrent at the frequency of said modulation component voltage and having a fixed phase With respect to said lmodulation component voltage, an oscillation generator controlled by said voltage pulses to produce non-sinusoidal Waves .recurrent e frecuency which is an odd subharmonic of the frequency of said pulses, ad- Justable phase shifting means for controlling the phase of said non-sinusoidal Waves with respect to said pulses, and iilter means for deriving the sinusoidal fundamental component voltage from said nonsinusoidal wave.

l. A device for deriving from a radiation eld with complex modulation a voltage harmonically related to one modulation component of said field, comprising an antenna for deriving a modulat'ed radio frequencyvoltage'from said field, a rectier and a filter for deriving a voltage correspendingy to one. modulation` component. of. said radlo. frequency voltage, Wave shape ino-dieaton me for producinairom. said modulation. come DoD-ent Voltage a train oif non-.sinusoidal voltage.

Waves, recurrent. etthe irecuency. ofsaid mcduiaf 0191.1 componer-.1t voltage arid having a. denite.

phase .rel-ation... thereto. adjustablenhasesnifting.

.. r controlling the. pbase. of said. non.-l vtaves. with respect. to. saidmadulatibn. voltage. endltermeans arranged to. d .moment voltage. Ware.

wa e

. e. rf hier .los i voltage. alternating.'

which'. is. related.. by.. an;y integral.

tiama circuit. @instable phase-shitting. means. f`

d u.. la. ator fer centraline .te emplitud@e` QI -seidee ttm'eielisieite .rsnaslcam and. @da transmitter* Connected. thereto' so. as t@ be; medulatedbyfthe-,out 

